A way of limiting renal fibrosis would be to decrease renal monocytic infiltration by promoting the differentiation of monocytes towards macrophages M2. Although more numerous, M2 macrophages no longer benefit the kidneys because the decline of M1 macrophages decrease renal MCP-1 production. Ex vivo IL1-β orients the differentiation of monocytes towards macrophages M1 and IL-4 to M2. By cons in vivo, the differentiating factors are poorly known. It is remarkable that metformin and telmisartan increase M2 macrophages M1 macrophages and decrease, respectively, in humans and mice. Moreover, telmisartan reduces proteinuria more than losartan in diabetic nephropathy in humans and Metformin decreases the amount of TGF-β intra-renal mice. This effect of telmisartan is independent of the type 1 receptor of angiotensin II (AT1R) since it is not obtained with losartan.